Ten Southern California branches of Pacific Western Bank were rebranded as Opus Bank on Monday.

The rebranding follows Opus’s acquisition of the locations from Pacific Western’s Century City holding company, PacWest Bancorp, which was announced in July and closed on Friday.

The acquisition enables Irvine-based Opus to enter the Inland Empire market and expand its presence in Los Angeles and San Diego. The affected branches include four in Los Angeles County: Westwood, Encino, Monrovia and South Pasadena. Also acquired were three branches in San Diego County, two in San Bernardino County and one in Riverside County. Employees at the Pacific Western branches have become employees of Opus.

“This transaction is consistent with Opus Bank’s long-term plan to build a relationship-based, super-community bank,” Opus Chief Executive Stephen H. Gordon said in a statement. Opus Bank now operates 57 banking offices, including 34 in California.

The deal enables Pacific Western, which has $5.4 billion in assets, to cut about $2 million in expenses. PacWest continues to operate 66 Pacific Western branches across the state.

PacWest shares were up 26 cents, or 1 percent, to $24.13 in late trading on Nasdaq.